Currently, seat boxes available on the market often comprise a main box defining a hollow interior space, wherein a rigid plank to which a cushion or a plurality of cushions are affixed rests on the main box such that the cushioned rigid plank is supported over the interior space. The advantage of this type of seat box simplicity in design that is easily constructed. However, the rigid plank is typically impermeable to moisture, such that, should the cushion become moist or wet, the cushion may not fully dry out while in place. The collection of moisture or wetness can reduce the serviceable life of the cushion. An attempted solution was replacing the conventional wooden rigid plank with an air permeable rigid seat plank. The inherent drawback of both the conventional rigid plank and the air permeable rigid seat plank is that the limited flexibility of the seat plank is uncomfortable to seated individuals. The air permeable rigid seat planks were replaced with high tensile strength webbing stretched across the main box, wherein the cushion is affixed to the webbing. The webbing provides the advantages of both a flexible seating surface and a permeable support structure for the cushion. However, any damage to the main box or the webbing due to misuse or other causes requires that the entire seat box be replaced. Due to the size and weight of the seat box, replacement of the entire seat box can be challenging and inconvenient.